The present invention relates generally to the design and use of medical devices, and more particularly, to a dialysis access system and method.
Access to a patient""s vascular system is necessary for a number of treatments such as hemodialysis, which is one of the most critical treatments, and other extra extracorporeal procedures. Hemodialysis, which is used for treatment of end-stage renal disease, involves connecting a patient to a dialysis or kidney machine. The dialysis machine cleanses the patient""s blood of waste products such as urea and potassium. Many patients must have this procedure done three or more times per week for the remainder of their lives.
Access to the patient""s vascular system for the purpose of withdrawing blood to be delivered to the dialysis machine and returning the dialyzed blood to the patient poses many challenges. A number of procedures have been used for this purpose. One method for chronic hemodialysis access is to create an arteria-venous fistula in the arm of a patient. With the fistula, which is a surgical connection of an artery to a vein, a number of changes occur. The connection bypasses flow-resistant capillaries to provide increased blood flow and the vein is caused to enlarge its diameter and the walls to thicken. Fistulas frequently last only about six months or so before clotting. Sometimes they can be de-clotted, but they remain problematic. Considerable resources are expended to keep such access systems in place and operating properly.
A fistula may not always be used because the patient""s blood vessels are not suitable for one reason or another. In such a case, a vascular graft may be used, which is essentially an artificial vessel applied between the artery and the vein. Thrombus or blood clots may partially or wholly occlude both of these approaches. Such blockage limits the blood flow for dialysis and reduces effectiveness of the process. Another problem is that the fistula or graft may become infected. An external catheter may be used temporarily in such situations, but again there are problems with infection and partial occlusion.
Another approach to providing access is to provide an implantable vascular access port at the proximal end of a catheter. With this approach, the connection of the dialysis machine to the patient can be made subcutaneously. Typically, these ports include a chamber and an access region, such as a septum, where the chamber is attached to an implanted catheter that in turn is secured to a blood vessel. In the case of veins, the catheter is typically an indwelling type. And in the case of arteries, the catheter may be attached by anastomosis. These too pose problems including the problem of clotting, venous occlusion, infection, septocpua and possible vein perforation.
Therefore, a need has arisen for a vascular access system and method that address shortcomings of previous systems and methods. According to an aspect of the present invention, a method of providing vascular access in a patient for hemodialysis that includes the steps of attaching the distal end of an access catheter to the abdominal aorta of the patient; attaching the proximal end of the access catheter to a portion of the patient to allow selective access to an interior portion of the access catheter; and wherein the access catheter is sized and configured to receive a blood-withdrawal catheter into the interior portion of the access catheter until the distal end of the withdrawal catheter is within the patient""s abdominal aorta and similarly a blood-return catheter.
According to another aspect of the present invention, a hemodialysis system for performing a hemodialysis treatment on a patient having an access catheter with the distal end of the access catheter coupled to the patient""s abdominal aorta and the proximal end coupled near an exterior portion of the patient for gaining selective access to an interior portion of the access catheter; a blood-withdrawal catheter disposed at least in part in the interior portion of the access catheter with the distal end of the withdrawal catheter in the patient""s abdominal aorta; a blood-return catheter disposed at least in part in the interior portion of the access catheter with the distal end of the blood return catheter in the patient""s abdominal aorta; and a hemodialysis machine fluidly coupled to the proximal end of the blood-withdrawal catheter and fluidly coupled to the proximal end of the blood-return catheter. According to another aspect of the present invention, a cutaneous port assembly is coupled to the proximal end of the access catheter for allowing selective access to the interior of the access catheter.
According to another aspect of the present invention, a method of performing a hemodialysis treatment in a patient having a vascular access system includes the steps of gaining access to an interior portion of an access catheter extending between a location near the patient""s exterior and the patient""s abdominal aorta; placing a blood-withdrawal catheter into an interior portion of the access catheter until a distal end of the blood-withdrawal catheter is within the patient""s abdominal aorta; placing a blood-return catheter into the interior portion of the access catheter until a distal end of the blood-return catheter is within the abdominal aorta; fluidly coupling a proximal end of the of the blood-withdrawal catheter to a hemodialysis machine; fluidly coupling a proximal end of the of the blood-return catheter to the hemodialysis machine; and performing hemodialysis with the hemodialysis machine with blood being removed from the patient through the blood-withdrawal catheter and returned through the blood-return catheter.
An advantage of the present invention is that it provides a convenient, high-blood flow access for hemodialysis. Another advantage of the present invention is that the access system will not have conduits susceptible to clotting that are directly used in the removal or return of blood for dialysis. The system and method provide for high flow that does not depend on the flow through a graft per se, but only as a conduit for hemodialysis catheters to pass through. Another advantage of the present invention is that the system will remain operable with acceptable performance in a patient for long periods of time.